Systems and methods for optimizing amplifier operations

ABSTRACT

Methods and systems for optimizing amplifier operations are described. The described methods and systems particularly describe a feed-forward control circuit that may also be used as a feed-back control circuit in certain applications. The feed-forward control circuit provides a control signal that may be used to configure an amplifier in a variety of ways.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of co-pending U.S. patent applicationSer. No. 15/487,328 filed Apr. 13, 2017 entitled “Systems and Methodsfor Optimizing Amplifier Operations”; and said application Ser. No.15/487,328 is a continuation of commonly owned U.S. patent applicationSer. No. 14/794,699 filed Jul. 8, 2015 entitled “Systems and Methods forOptimizing Amplifier Operations” (now U.S. Pat. No. 9,712,120 issuedJul. 18, 2017); and application Ser. No. 14/794,699 is a divisional of,and claims the benefit of priority to, U.S. patent application Ser. No.13/828,121 filed Mar. 14, 2013 and entitled “Systems and Methods forOptimizing Amplifier Operations” (now U.S. Pat. No. 9,595,923 issuedMar. 14, 2017). This application incorporates by reference theabove-identified application Ser. Nos. 13/828,121, 14/794,699 and15/487,328 as if set forth in full.

1. FIELD

The present teachings relate to amplifiers. In particular, the presentteachings relate to optimizing amplifier operation by providing afeed-forward control signal that is used to affect amplifier operationin one or more ways.

2. DESCRIPTION OF RELATED ART

Amplifier gain is typically maintained over a range of operatingconditions by using a feedback control circuit. For example, thefeedback control circuit monitors the amplitude of an output signal ofthe amplifier and detects any variation of this amplitude from a nominalvalue. Based on the detected variation, the feedback control circuitgenerates a feedback control signal that is applied back upon theamplifier (input) so as to either increase, or to decrease the amplifiergain and bring the output signal of the amplifier to the nominal value.However, this gain feedback operation may result in adversely impactingthe output signal, for example the control loop may be too slow or maybecome unstable. Furthermore, closed loop operation typically involvesmore active and/or passive circuit blocks, which can lead to size andpower consumption issues. Closed loop systems also have limitedbandwidth, and may be susceptible to interference issues as well.

Furthermore, the typical feedback control circuit monitors only alimited set of parameters, for example, the amplitude and/or phase of anoutput signal and uses these monitored values to modify such parametersof the input signal as the input signal propagates through the amplifiercircuit, thus overlooking other parameters that may be of equal orgreater importance in certain applications.

SUMMARY

According to a first aspect of the present disclosure, a system foroptimizing amplifier operations is provided. The system includes anamplifier configured to receive an input signal and generate therefrom,an output signal having a desired characteristic; and also includes afeed-forward control circuit configured to receive said input signal,analyze said input signal, and generate a control signal that isprovided to the amplifier for impressing the desired characteristic uponsaid output signal.

According to a second aspect of the disclosure, a system for optimizingamplifier operations is provided. The system includes an amplifierconfigured to receive an input signal and provide an amplitude gain tosaid input signal; and further includes a control circuit configured toreceive said input signal, analyze at least one characteristic of saidinput signal and generate a control signal that is provided to theamplifier for generating the amplitude gain.

According to a third aspect of the disclosure, a method for optimizingamplifier operations is provided, the method comprising: analyzing aninput signal; generating a feed-forward control signal based upon saidanalyzing; providing the input signal and the feed-forward controlsignal to an amplifier; and using the feed-forward control signal tomodify at least one of a) an operating characteristic of the amplifieror b) a physical aspect of an element contained in the amplifier.

Further aspects of the disclosure are shown in the specification,drawings and claims of the present application.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present disclosure can be better understood withreference to the following drawings. The components in the drawings arenot necessarily drawn to scale. Instead, emphasis is placed upon clearlyillustrating various principles. Moreover, in the drawings, likereference numerals designate corresponding parts throughout the severalviews.

FIG. 1 shows an amplifier system incorporating a feed-forward controlcircuit coupled to an amplifier.

FIG. 2 shows an alternative embodiment of the amplifier system shown inFIG. 1.

FIG. 3 shows a few components that may be incorporated into thefeed-forward control circuit shown in FIG. 1.

FIG. 4 shows a few components that are contained in a measurementcircuit that is used to generate derived data provided to thefeed-forward control circuit of FIG. 3.

FIG. 5 shows a few components that are contained inside the amplifiershown in FIG. 1.

FIG. 6 shows a few components that may be incorporated into a signalmodification block of the amplifier shown in FIG. 5.

FIG. 7 show an exemplary scalable periphery tunable matching (SPTM)power amplifier architecture.

DETAILED DESCRIPTION

Throughout this description, embodiments and variations are describedfor the purpose of illustrating uses and implementations of theinventive concept. The illustrative description should be understood aspresenting examples of the inventive concept, rather than as limitingthe scope of the concept as disclosed herein. For example, it will beunderstood that terminology such as nodes, terminals, voltage drops,circuits, blocks, connections, lines, and coupling are used herein as amatter of convenience for description purposes and should not beinterpreted literally in a narrow sense. Furthermore, the words “block”or “functional blocks” as used herein refer not only to a circuitcontaining discrete components or integrated circuits (ICs), but mayalso refer to various other elements such as a module, a sub-module, ora mechanical assembly. Similarly, the word “line” as used herein mayrefer to various connectivity elements such as a wire, a cable, a coppertrack on a printed circuit board, an optical fiber, or a wireless link.Also, it must be understood that the word “example” as used herein (inwhatever context) is intended to be non-exclusionary and non-limiting innature. A person of ordinary skill in the art will understand theprinciples described herein and recognize that these principles can beapplied to a wide variety of applications using a wide variety ofphysical elements.

In particular, described herein are some systems and methods pertainingto optimizing amplifier operation by using a feed-forward controlcircuit. As can be understood by one of ordinary skill in the art, thedescribed systems and methods can be incorporated into a wide variety ofamplifier systems, and furthermore such amplifier systems may be used ina variety of devices and applications spanning a variety of operatingconditions (frequencies, voltages, power etc). The term feed-forwardimplies that the control circuit derives a control state or conditionsbased on inputs to the circuit under control, and not from an output ofthe circuit under control. If using the output of the circuit undercontrol and feeding it back in a closed loop manner to the input orother control port to lock a control loop would imply a feedbackcircuit.

FIG. 1 shows an amplifier system 100 that includes an amplifier 110 anda feed-forward control circuit 105. An input signal is provided toamplifier 110 via line 101 a. The same input signal is also provided tofeed-forward control circuit 105 via line 101 b. In one exampleembodiment, the input signal is a radio-frequency (RF) signal. However,it will be understood that the input signal may occupy lower frequencybands, as well as higher frequency bands, in other applications.

Feed-forward control circuit 105 is configured for monitoring one ormore parameters of the input signal and using this information togenerate a control signal that is provided via line 102 to amplifier 110in order to modify one or more signal characteristics of the inputsignal, either by directly affecting the input signal to the amplifier,or by affecting a characteristic of the amplification path the inputsignal is subjected to within the amplifier. The input signal asaffected by the control signal is then provided via line 103 as anoutput signal from amplifier 110. A few examples of one or moremonitoring functions that may be carried out by feed-forward controlcircuit 105 upon the input signal that is provided to the feed-forwardcontrol circuit 105 via line 101 b, include: a power level measurement,a frequency measurement, a spectral content measurement, apeak-to-average level variation measurement, a peak-to-minimum levelvariation measurement, a bandwidth measurement, and/or signal analysisusing polar (amplitude and phase) and/or Cartesian coordinates (I & Qcomponents). Some of these functions will be described below in moredetail using other figures.

FIG. 2 shows an alternative embodiment of the amplifier system 100 shownin FIG. 1. In this alternative embodiment, referred to herein asamplifier system 200, one or more additional inputs in addition to theinput signal carried on line 101 b, may be provided to feed-forwardcontrol circuit 105. Of the two additional inputs shown, a first inputincludes control data that is provided from a controller 205 via line201, while a second input includes data that has been derived in ameasurement circuit 210 and provided to feed-forward control circuit 105via line 202.

The additional inputs provide information that may be also used byfeed-forward control circuit 105 to generate the control signal carriedon line 102. In various alternative embodiments, feed-forward controlcircuit 105 may use only one of the two additional inputs, may use oneor both additional inputs in lieu of the input signal provided via line101 b, or may use one or both the additional inputs in a complementarymanner in conjunction with the input signal provided via line 101 b.

In one embodiment, information derived from the input signal (line 101b) is combined with information derived from one or both of theadditional inputs (lines 201 and 202) and the combined information isused to generate the control signal carried on line 102. For example,the information derived from the input signal may pertain to a powerlevel of the input signal, and the information derived from the controldata (line 201) may pertain to a desired power level. Feed-forwardcontrol circuit uses these two pieces of information to generate acontrol signal that configures amplifier 110 to produce an output signal(via line 103) at the desired power level. In one embodiment, thecontrol signal is generated autonomously using multiple pieces ofinformation rather than a single piece of information (for example, afeedback signal, or a signal received from a transceiver unit) therebypermitting various control operations to be carried out, some of whichare described below. A non-exhaustive list of the multiple pieces ofinformation includes: power level, battery voltage, temperature,peak-to-peak and/or peak-to-average modulation-related measurements,amplifier-specific information, and other information such asincorporated into system 200 during design, factory test and/orcalibration. The autonomously derived control signal derived in thismanner provides a more intelligent configuration for system 200.

In another embodiment, information derived from the input signal (line101 b) may be used at a first instant in time to derive a first controlsignal carried on line 102, and at a subsequent instant in time, one orboth of the additional inputs (lines 201 and 202) may be used to derivea second control signal that is also carried on line 102. Such anoperation may be deemed a time-multiplexing operation and the controlsignal derived therefrom, a time-multiplexed control signal.

A few examples of other types of information derived by feed-forwardcontrol circuit 105 from the control data provided via line 201 includesone or more desired operating conditions for amplifier 110. Such desiredoperating conditions include for example: a desired level of powerconsumption from a power supply, a power-down mode, a modulation schemeto be applied upon the input signal, and a reconfiguration of one ormore elements (switching, re-routing signal paths etc.) of the amplifier110.

Controller 205 may be implemented in a variety of ways, such as forexample, using a processor circuit, a state machine, and/or a dedicatedcontrol circuit formed of various ICs. The control data provided vialine 201 may include one or more of the following: instructions such asmodulation mode, frequency band, frequency of operation, power level,raw data, trigger conditions, and/or gating logic. It will be understoodthat the control data provided via line 201 and the derived dataprovided via line 202 may be implemented in a digital format and/or ananalog format. Measurement circuit 210 is described below in more detailusing FIG. 4.

Attention is now drawn to FIG. 3, which shows a few components that maybe incorporated into feed-forward control circuit 105. It will be notedthat several connecting links are shown as dashed lines in order toindicate that there may be one or more functional blocks (not shown)that may be intermedially located in such connecting links. A fewexamples of such intermedial functional blocks include signal receivers,signal drivers, amplifiers, attenuators, and various signal conditioningcircuits. It will also be noted that several functional blocks are shownin dashed lines in order to indicate that these functional blocks may beoptionally used. Consequently, in certain applications, one or more ofsuch functional blocks may be included while others may be omitted.Furthermore, it should be understood that the functional blocks shown inFIG. 3 are intended merely as examples for purposes of description andseveral additional/alternative functional blocks may be used in variousimplementations.

Input signal monitoring circuit 300 carries out various types ofmonitoring operations upon the input signal that is fed in via line 101b, and provides a monitoring result (via line 301) to control signalgenerator 350. Control signal generator 350 may use this monitoringresult to generate the control signal on line 102.

Of the various functional blocks shown inside input signal monitoringcircuit 300, power level detector 305 may be used to monitor and detecta power level of the input signal. The result of this action is providedto control signal generator 350, which may then use this result inconjunction with control data provided via line 201, to generate acontrol signal (on line 102) for configuring amplifier 110 to producethe output signal at a desired power level. Thus, if the monitoringresult indicates a low power level on the input signal, the controlsignal on line 102 configures amplifier 110 to boost the power level ofthe output signal to the desired power level; and vice-versa. The lowpower level indication may be used for other purposes as well, such as,for example, setting amplifier 110 to operate in a low power mode, orvarying operating parameters of amplifier 110, such as bias, settingdevice size, load line etc. Examples of such operating parametersaffecting characteristic response of the amplifier may be found in U.S.application Ser. No. 13/797,779 entitled “Scalable Periphery TunableMatching Amplifier”, filed on Mar. 12, 2013, and incorporated herein byreference in its entirety [now U.S. Pat. No. 9,294,056 B2, issued Mar.22, 2016].

Frequency detector 310 may be used to monitor and detect one or morefrequencies that are present in the input signal. Additional information(e.g. amplitude, distortion level, etc.) pertaining to this detectedfrequency may also be detected. The result of this action is provided tocontrol signal generator 350, which may then use this result inconjunction with control data provided via line 201 (a desired frequencycharacteristic, for example) to generate a control signal on line 102that configures amplifier 110 to impress the desired frequencycharacteristic upon the output signal. The control signal on line 102may be used for various other operations such as to tune a passivenetwork inside amplifier 110.

Voltage level detector 320 operates in manner similar to that describedabove with reference to power level detector 305. Voltage leveldetection may be employed when the input signal has a lower frequency(audio, base-band etc), while power level detection may be employed whenthe input signal is an RF signal, for example. The person skilled in theart will understand, upon reading of the present disclosure, that powerlevel detection for RF signals may be appropriate because voltage leveldetection may be difficult at RF frequencies.

Bandwidth detector 325, spectral analyzer 330, and modulation detector335, individually or in various combinations with each other, may beused to monitor and identify the spectral nature of the input signal, aswell as to measure various parameters such as peak-to-average ratio,peak-to-minimum, modulation bandwidth, etc. The result of this action isprovided to control signal generator 350, which may then use the resultin conjunction with control data provided via line 201 to generate acontrol signal (line 102) that configures amplifier 110 to modify acharacteristic of the output signal at line 103. The configuring processmay include for example, the insertion and/or removal of afrequency-related component (filter, etc) into one or more signal pathsin amplifier 110 or for adjusting bias, amplifier device size, matchingetc.

Control signal generator 350 uses information provided on one or morelines 201, 202 and 301 to generate the control signal on line 102. Inone embodiment (as shown in FIG. 1), control signal generator 350 usesonly the monitoring result provided on line 301 by input signalmonitoring circuit 300. In this one embodiment, lines 201 and 202 maynot be present, and if present, are not used.

In another embodiment, the monitoring result provided on line 301 byinput signal monitoring circuit 300 is used in conjunction with one orboth the control data and the derived data provided on lines 201 and 202respectively. Some examples of such usage have been described above.

In an additional example, control signal generator 350 processes themonitoring result provided on line 301 based on certain conditionalrequirements provided via the control data on line 201. The conditionalrequirements may be implemented in a logic format. Thus, the controlsignal that is generated by the control signal generator 350 from themonitoring result, has a first format when the control data provided vialine 201 has a first logic state (a logic “1”, for example), and has adifferent format when the control data has a second logic state (a logic“0”, for example).

The nature of the derived data that is provided via line 202 to controlsignal generator 350 will now be described using FIG. 4, which shows afew components that are contained in measurement circuit 210 and areused to generate the derived data. Functional blocks 410, 415, 420, 425and 430 operate in manner similar to that described above with referenceto functional blocks 305, 310, 320, 325 and 330 of FIG. 3. However, itwill be noted that functional blocks 305, 310, 320, 325 and 330 of FIG.3 operate upon the input signal (provided via line 101 b), whereasfunctional blocks 410, 415, 420, 423, 425 and 430 operate on one or moresignals other than the input signal. Two types of such signals are shownin FIG. 4. In one embodiment, one or both of these signals are providedin a digital format, in another embodiment one or both of these signalsare provided in an analog format, while in yet another embodiment, oneof the signals is provided in an analog format and the other in adigital format.

The first signal is a monitored output signal, which provides a sampleof the output signal that is generated by amplifier 110 on line 103 (asshown in FIG. 1). This configuration may be viewed as a part of afeed-back control circuit in the sense that the sample of the outputsignal is used for generating the control signal (on line 102), which isthen used to configure 102. However, it must be noted that thisfeed-back configuration does not merely operate as a gain controlfeed-back circuit for continuously changing the gain of amplifier 110 inaccordance with output signal changes, but operates as a configurationcontrol feedback circuit. The configuration control does not merelyoperate to change amplifier gain, but is operative to carrying out ahost of other functions (switching operations, physical pathmodification, power supply consumption control etc) based on themonitored (e.g. sampled) output signal, that are described below in moredetail.

In addition to being operated upon by functional blocks 410, 415, 420,423, 425 and 430 for obtaining related information (power level, voltagelevel, bandwidth, and spectral data), the monitored output signal mayalso be provided to VSWR detector 435 and/or load mismatch detector 440.One or both of these functional blocks may be used to determine animpact of an output load (described below using FIG. 5) that isconnected to line 103 of amplifier 110. VSWR detector 435 and/or loadmismatch detector 440 provide information to control signal generator350 (FIG. 3) for generating the control signal that may be used tomanipulate a load matching block in amplifier 110 in order to addressand overcome any adverse effect that may be present as a result of theoutput load upon output signal 103 of amplifier 110. If desired, voltagedetector (420) can be used to detect battery voltages and other supplyor reference voltages. Temperature detector (423) can be used to detecton-chip or off-chip temperatures, while circuit element detector (424)can be used to measure component parameters such as inductance,capacitance, threshold voltage, and such. If desired, a modulationdetector can also be provided. In case of a scalable periphery amplifieras described by U.S. patent application Ser. No. 13/797,779 alreadymentioned above, the output tunable match may be used for this purpose.Further details about tunable matching networks may be found in examplein U.S. Pat. No. 7,795,968 B1, issued on Sep. 14, 2010, which isincorporated herein by reference in its entirety.

The second signal that is provided to measurement circuit 210 is a datainput on line 408. Such data may be provided in either digital form orin analog form. Furthermore, the type of data provided may vary from oneimplementation to another. In one case, the data may be raw data whilein another case, the data may be processed data that is generated in aprocessing device (not shown) such as a processor circuit, ananalog-to-digital converter circuit etc. A few examples of data inputinclude temperature data (alternatively or in addition to thetemperature data provided by temperature detector (423)), power supplydata, battery data, biasing data, various types of signal levels (alsoinclusive of frequency and/or power levels), logic level conditions(inclusive of mode and/or modulation), switch position data, physicallocation data that may impact reception of a signal (cellular towers),etc.

The temperature data may be obtained for example by using a temperatureprobe 120 (see, e.g., the alternative embodiment shown in FIG. 2) placedat any suitable monitoring point in amplifier system 100 (shown in FIG.1). The power supply and/or battery data may be obtained by monitoringvoltage and/or current at one or more monitoring points in amplifiersystem 100. The biasing data may be obtained by monitoring voltage biasat one or more monitoring points in amplifier system 100, such as forexample a gate, a drain, and/or a source terminal of a field-effecttransistor that is a part of amplifier 110. The physical location datamay be obtained by a GPS chip or equivalent included within a portabledevice (cell phone, tablet, etc.).

Attention is now drawn to FIG. 5, which shows a few components ofamplifier 110 and the action of feed-forward control circuit 105 uponamplifier 110. The components are shown as two functional blocks thatmay be used individually or in combination in different embodiments. Thefunctional blocks are intended merely as examples for purposes ofdescription and several additional/alternative functional blocks may beused in various embodiments. Also, one or more blocks may be merged intoother blocks in various implementations. For example, load matchingblock may be merged into signal modification block 505, and may beconfigured as an inter-stage matching circuit for example.

The control signal provided on line 102 by feed-forward control circuit105 may be coupled to various elements contained inside amplifier 110.Two such connections, which may be used individually or combinedly, areshown. The first connection is provided to a signal modification block505, which is described below in more detail using FIG. 6, while thesecond connection is provided to a load matching block 510. When derivedfrom functional blocks such as VSWR detector 435 or load mismatchdetector 440, the control signal is used to configure the load matchingblock 510 to provide a suitable matching impedance that results in adesired VSWR or desired power level transfer from amplifier 110 intoload 515. The skilled person will know various methods of realizing sucha load matching block, such as, for example, a tunable matching network.

As a part of this action, an RF load line stored in a memory (not shown)may be used by control signal generator 350 in order to generate acontrol signal that configures a tunable circuit, for example, containedin load matching block 510, such as a tunable matching network.Configuring the tunable circuit may be implemented in various ways suchas by operating switches that switch in/out one or more impedanceelements (e.g. capacitors, inductors, etc.), or by providing one or morecontrol voltages to one or more variable impedances (e.g. varactors,tunable capacitors, etc.). Details regarding tunable reactive elements,including tunable capacitors and inductors, are described, for example,in PCT publication number WO2009/108391 entitled “Method and Apparatusfor use in Digitally Tuning a Capacitor in an Integrated CircuitDevice”, published on Sep. 3, 2009, and in U.S. patent application Ser.No. 13/595,893 entitled “Method and Apparatus for Use in TuningReactance in an Integrated Circuit Device”, filed on Aug. 27, 2012, bothincorporated by reference herein in their entirety, where examples ofdigital tuning capacitors and/or digital tuning inductors for use in atunable matching network are disclosed. In many embodiments of thepresent disclosure, the switching circuitry can be constructed usingCMOS technology and various architectures known to the skilled person,such as, for example, the architecture presented in U.S. Pat. No.7,910,993, issued on Mar. 22, 2011 and entitled “Method and Apparatusfor use in Improving Linearity of MOSFET's using an Accumulated ChargeSink”, and in U.S. Pat. No. 6,804,502, issued on Oct. 12, 2004 andentitled “Switch Circuit and Method of Switching Radio FrequencySignals”, both of which are incorporated herein by reference in theirentirety.

Furthermore, load matching block 510 may be configured in conjunctionwith signal modification block 505 in various ways as well. In general,such operations may be directed at carrying out one or more of thefollowing: changing a bias voltage; changing a bias current; changing asupply voltage (for example, by changing the switching frequency of aDC-DC converter, or by operating upon a gain/attenuation element);switching in or out one or more stages of a multi-stage gain unit;modifying the physical size of one or more elements; modifying amplifiergain, phase and/or compression points; and/or enable/disable one or moreelements, such as unit cells of a scalable periphery amplifier.

Typically, in the case where amplifier 110 is a power amplifiercontained inside a cell phone for example, the power amplifier isconfigured for maximum efficiency when operated in a saturated mode ofoperation. However, when the input signal to the power amplifier isreduced, the power amplifier operates further away from saturation andthus operates in a less efficient manner. The sub-optimal performanceresults in various adverse conditions such as excessive current drainand a resulting reduction in battery life. While certain steps may betaken to reduce the excessive current drain from the battery, care mustbe taken that such steps are performed in a smooth and intelligentfashion so as to avoid abrupt and undesirable changes in the outputsignal. For example, cutting out one or more stages of a multi-stageamplifier, or activating/deactivating unit cells within a scalableperiphery amplifier, may indeed lead to a reduction in the excessivecurrent. However, if this action is carried out without care, theamplifier's transfer function may be adversely affected and a noticeableand undesirable discontinuity created in the output signal.

The control signal provided by feed-forward control circuit 105 may beused to carry out a smooth transition from one operating condition toanother by performing one or more operations upon the signalmodification block 505 and/or the load matching block 510. In broadterms, operating upon the signal modification block 505 may be describedas altering one or more operating parameters and/or size parameters(such as a current size within an output drain, or impedance/trace sizeto affect current and/or introduce delay) of amplifier 110. In oneembodiment, altering one or more operating parameters may be carried outby using a lookup table 352 that may be a part of feed-forward controlcircuit 105. The look-up table 352 provides a set of values for variousparameters of amplifier 110 that may be altered in a controlled mannerwithout a radical change in the transfer function of amplifier 110 or anabrupt change in output power (e.g. performing a series of small stepchanges to gradually reach the desired output power). A few examples ofthe various parameters that may be controlled via the values stored inthe look-up table 352 may include: current draw, voltage bias at one ormore nodes of amplifier 110, amplitude of the output signal, phase ofthe output signal, transition times for edges of signals at one or morenodes of amplifier 110, size of the amplifier in case of, e.g., ascalable periphery amplifier like the one disclosed in the abovementioned U.S. patent application Ser. No. 13/797,779, and signal delay.In general, the lookup table 352 can contain any mapping of an input tothe feed-forward control circuit (105) with its output connected to thesignal modification block (505) as shown in FIG. 5.

Dashed lines 407 a and 407 b indicate two of several optional monitoringpoints from which an output monitored signal may be generated by usingsuitable circuitry (not shown). The monitored output signal is providedto measurement circuit 210 (via line 407) as shown in FIG. 4.

Attention is now drawn to FIG. 6, which shows some functional blocksthat may be included in signal modification block 505. The functionalblocks are shown in dashed lines in order to indicate that thesefunctional blocks may be used individually or in various combinations indifferent embodiments. Furthermore, the functional blocks shown in FIG.6 are intended merely as examples for purposes of description andseveral additional/alternative functional blocks may be used in variousembodiments. Also, one or more blocks may be merged into other blocks invarious implementations. Additionally, if desired, any one of theparameters described in FIG. 6 can be provided by way of a look-up tableas described above.

Gain stage 605 may include one more gain stages for amplifying the inputsignal provided on line 101 a. The control signal provided on line 102may be used to configure gain stage 605 in various ways. For example,the control signal may be used to reduce the overall gain of amplifier110 by cutting out one or more amplifier stages or unit cells of ascalable periphery amplifier at a suitable time, such as when the inputsignal is not present on line 101 a, thereby avoiding any adversechanges upon the output signal when the input signal is subsequentlypresented on line 101 a.

As yet another example, the control signal provided on line 102 may beused to switch power supply current flow and/or input signal flowthrough one or more alternative paths. Such switching may be carried outvia path modifier 630, which may be included in gain stage 605, and isdirected at changing the amount of impedance presented by a signal pathfor the current flow and/or input signal flow. Changing the amount ofimpedance may be carried out by inserting or removing various componentssuch as resistors, inductors, PCB tracks, and other impedance elements.Such path modifier may include a tunable matching network such asdescribed in the above mentioned U.S. application Ser. No. 13/797,779,incorporated herein by reference in its entirety. The power supplycurrent aspects may be addressed by the control signal via power supplycontrol 620, which may include suitable switches and other controlcircuitry. The control circuitry may include one or more circuits thatare used to change the switching frequency (and consequently, the outputvoltage) of a switching supply when used in amplifier 110.

Bias adjustment 615 may be used for various purposes. For example, whenit is desired to reduce (or increase) current/power consumption inamplifier 110, bias adjustment 615 may be configured to reduce theamount of current provided to one or more stages. Such reduction may becarried out in a gradual manner thereby avoiding abrupt changes upon theamplification action performed by amplifier 110. Furthermore, in oneembodiment, the reduction in current may be carried out in conjunctionwith attenuator 610, which may be included inside bias adjustment 615.Conversely, current provided to one or more stages may be increased ifso desired (for example, to provide more output power from amplifier110). Other examples of bias adjustments to affect amplifier responseare presented, for example, in the above mentioned U.S. application Ser.No. 13/797,779, incorporated herein by reference in its entirety.

Signal delay 625 may be used in certain applications where it is desiredto carry out real-time functions upon the input signal. To elaborateupon this aspect, attention is drawn to FIG. 1, which shows the inputsignal provided via line 101 b to feed-forward control circuit 105. Asdescribed above, feed-forward control circuit 105 uses this input signaland generates the control signal on line 102. As can be understood, theoperations performed in feed-forward control circuit 105 will take acertain amount of time. During this operational delay, the input signalcarried on line 110 a is presented to amplifier 110 and if leftundelayed, will propagate through amplifier 110 without the controlsignal being available for application upon the input signal at thatinstant in time. This may be undesirable in certain real-timeapplications. Consequently, signal delay block 625 shown in FIG. 6 isused to provide a signal delay that may be equal to, or greater than,the amount of time feed-forward control circuit 105 takes to generatethe control signal.

It will be understood, however, that in non-real time applications (forexample, when the input signal is of a repetitive and relativelytime-invariant nature), signal delay 625 may be controllably cut outusing the control signal, or completely eliminated. The delay infeed-forward control circuit 105 is inconsequential because the controlsignal may be applied upon amplifier 110 so as to affect a differentportion of the input signal, without any adverse impact of such anaction upon the overall system performance. Alternatively, the delay canalso be used in a non-real time manner to adjust delays within thecircuits and system.

FIG. 7 shows an exemplary scalable periphery tunable matching (SPTM)power amplifier architecture 700 that may be used as the amplifier 110of FIG. 5 under the control of line 102. A similar architecture can alsobe found in U.S. Pat. No. 7,170,341, issued on Jan. 30, 2007 andentitled “Low Power Consumption Adaptive Power Amplifier”. By way ofexample, and not of limitation, the SPTM power amplifier architecture700 can further comprise a tunable input matching network 710 connectedto the input of a scalable periphery amplifier 720, the output of whichis connected to a tunable output matching network 730. The scalableperiphery amplifier 720 comprises a plurality of unit cells. Varyingamplifier power levels (i.e., gain) can be accommodated by selectivelyactivating or deactivating such unit cells by means of a coupled controlsignal. Operation and details of particular embodiments of the SPTMpower amplifier architecture 700 are as set forth in U.S. patentapplication Ser. No. 13/797,779 already mentioned above.

The person skilled in the art will also appreciate that the systems,components, and methods described herein allow for optimized amplifieroperations. While the devices and methods have been described by meansof specific embodiments and applications thereof, it is understood thatnumerous modifications and variations could be made thereto by thoseskilled in the art without departing from the spirit and scope of thedisclosure. It is therefore to be understood that, within the scope ofthe claims, the disclosure may be practiced otherwise than asspecifically described herein.

A person skilled in the art will also be aware that the architecture ofthe present disclosure (e.g. as shown in the attached figures) may beconstructed on a single chip where all components are integratedmonolithically, or alternatively some components may be partiallyintegrated (or not at all). Various configurations and correspondingpartitioning within a single or multiple chips may depend on the usedcomponents and related technologies.

The techniques disclosed in the present application can be furtherapplied in conjunction with other amplifier efficiency improvement andperformance techniques such as analog pre-distortion, digitalpre-distortion, Doherty amplifiers, LINC (linear amplification withnonlinear components) or outphasing amplifiers, switching amplifierssuch as Class S and Class M, and also distributed amplifiers, amongothers. The skilled person will thus appreciate the flexibility andadaptability of the various embodiments of this disclosure to otherknown configurations and techniques. Additionally, although severalembodiments of the present disclosure are directed at RF amplifiers, theperson skilled in the art will understand that such embodiments can beapplied to other amplifiers as well, such as audio, cable distribution,and other types of amplifiers.

A number of embodiments of the present inventive concept have beendescribed. Nevertheless, it will be understood that variousmodifications may be made without departing from the scope of theinventive teachings.

Accordingly, it is to be understood that the inventive concept is not tobe limited by the specific illustrated embodiments, but only by thescope of the appended claims. The description may provide examples ofsimilar features as are recited in the claims, but it should not beassumed that such similar features are identical to those in the claimsunless such identity is essential to comprehend the scope of the claim.In some instances the intended distinction between claim features anddescription features is underscored by using slightly differentterminology.

What is claimed is:
 1. A system for optimizing amplifier operations,including: (a) a scalable periphery amplifier configured to receive aradio frequency input signal, the scalable periphery amplifier includinga plurality of selectable unit cells for providing an adjustable amountof gain to the input signal by applying the input signal to a selectionof one or more of the plurality of selectable unit cells; and (b) afeed-forward control circuit, coupled to the scalable peripheryamplifier and to the input signal, configured to receive the inputsignal and generate a control signal that is derived from at least onecharacteristic of the input signal and which is provided to the scalableperiphery amplifier for adjusting the amount of gain of the scalableperiphery amplifier.
 2. The system of claim 1, wherein the at least onecharacteristic of the input signal includes an amplitude of the inputsignal, and wherein adjusting the amount of gain includes applying thecontrol signal to the scalable periphery amplifier to enable or disableselected ones of the one or more plurality of unit cells of the scalableperiphery amplifier and/or to modify a bias point in the scalableperiphery amplifier.
 3. A system for optimizing amplifier operations,including: (a) an amplifier configured to receive an input signal and acontrol signal, and generate an output signal in response to the inputsignal and the control signal, the output signal having a desiredcharacteristic that includes at least one of a power level, amplifiergain, a voltage range, or a current level; (b) a temperature probeplaced at a monitoring point in the amplifier and configured to output adata representing a temperature; (c) a measurement circuit coupled tothe temperature probe and including at least a temperature detectorconfigured to measure a temperature based on the temperature probeoutput data and to output a derived data signal as a function of suchtemperature measurement; and (d) a feed-forward control circuitincluding a look-up table, the feed-forward control circuit coupled tothe amplifier, to the input signal, and to the measurement circuit, thefeed-forward control circuit configured to receive the derived datasignal and to receive and analyze the input signal, apply the analyzedinput signal and the derived data signal to the look-up table togenerate the control signal, and provide the control signal to theamplifier to modify at least one operating characteristic of theamplifier as a function of at least temperature, thereby altering thedesired characteristic of the output signal.
 4. The system of claim 3,further including a configurable load matching block, coupled to thefeed-forward control circuit, for modifying at least one of amplifiergain, amplifier phase, and/or amplifier compression points as a functionof the control signal.
 5. A system for optimizing amplifier operations,including: (a) an amplifier configured to receive an input signal and acontrol signal, and generate an output signal in response to the inputsignal and the control signal, the output signal having a desiredcharacteristic that includes at least one of a power level, amplifiergain, a voltage range, or a current level; (b) a measurement circuitincluding at least one detector or analyzer configured to measure aselected characteristic of at least one data or monitored signal inputand to output a derived data signal as a function of such measurement;and (c) a feed-forward control circuit including a look-up table, thefeed-forward control circuit coupled to the amplifier, to the inputsignal, and to the measurement circuit, the feed-forward control circuitconfigured to receive the derived data signal and to receive and analyzethe input signal, apply the analyzed input signal and the derived datasignal to the look-up table to generate the control signal, and providethe control signal to the amplifier to modify at least one operatingcharacteristic of the amplifier, thereby altering the desiredcharacteristic of the output signal.
 6. The system of claim 5, whereinthe measurement circuit includes at least a power level detectorconfigured to measure a power level represented by the at least one dataor monitored signal input and to output the derived data signal as afunction of such measurement.
 7. The system of claim 5, wherein themeasurement circuit includes at least a frequency detector configured tomeasure a frequency represented by the at least one data or monitoredsignal input and to output the derived data signal as a function of suchmeasurement.
 8. The system of claim 5, wherein the measurement circuitincludes at least a voltage level detector configured to measure avoltage represented by the at least one data or monitored signal inputand to output the derived data signal as a function of such measurement.9. The system of claim 5, wherein the measurement circuit includes atleast a temperature detector configured to measure a temperaturerepresented by the at least one data or monitored signal input and tooutput the derived data signal as a function of such measurement. 10.The system of claim 5, wherein the measurement circuit includes at leasta bandwidth detector configured to measure a bandwidth represented bythe at least one data or monitored signal input and to output thederived data signal as a function of such measurement.
 11. The system ofclaim 5, wherein the measurement circuit includes at least a spectralanalyzer configured to measure spectral data represented by the at leastone data or monitored signal input and to output the derived data signalas a function of such measurement.
 12. The system of claim 5, whereinthe measurement circuit includes at least a Voltage Standing Wave Ratio(VSWR) detector configured to measure a VSWR represented by the at leastone data or monitored signal input and to output the derived data signalas a function of such measurement.
 13. The system of claim 5, whereinthe measurement circuit includes at least a load mismatch detectorconfigured to measure a load mismatch represented by the at least onedata or monitored signal input and to output the derived data signal asa function of such measurement.
 14. The system of claim 5, wherein themeasurement circuit includes at least a circuit element detectorconfigured to measure at least one parameter of a circuit component,where such at least one parameter is represented by the at least onedata or monitored signal input, and to output the derived data signal asa function of such measurement.
 15. The system of claim 5, wherein theat least one data or monitored signal input includes signals or datarepresenting one or more of: an output power level from the amplifier,temperature data, power supply data, battery data, biasing data, signallevel data, voltage level data, frequency data, power level data, logiclevel conditions, switch position data, physical location data, mode ofoperation of the amplifier, a modulation format of the output signal,and/or load mismatch data.
 16. The system of claim 5, wherein theamplifier includes a signal modification block, and wherein the controlsignal configures the signal modification block.
 17. The system of claim16, wherein the signal modification block includes one or more of: again stage block, an attenuator block, a bias adjustment block, a powersupply control block, a signal delay block, or a path modifier block,wherein at least one included block has one or more parameters alterableby the control signal input to reconfigure the signal modificationblock.
 18. The system of claim 5, wherein the amplifier includes a loadmatching block, and wherein the control signal configures the loadmatching block.
 19. The system of claim 18, wherein the load matchingblock is configurable by one or more of: matching impedances to providea desired Voltage Standing Wave Ratio or desired power level transferfrom the amplifier into a load, switching one or more impedance elementsin or out of circuit in a tunable matching network, providing one ormore control voltages to one or more variable impedances in the tunablematching network, changing a bias voltage, changing a bias current,changing a supply voltage, switching in or out one or more stages of amulti-stage gain unit, modifying the physical size of one or moreelements, modifying amplifier gain, modifying amplifier phase, modifyingamplifier compression points, and/or enabling or disabling one or moreelements.